(A) Field of the Invention
The present invention is related to a method and an apparatus for decoding multiword information, which are applied to an optical disk device.
(B) Description of the Related Art
As shown in FIG. 1, an Error Correction Code (ECC) cluster 10 includes 152 long-distance code (LDC) data columns, one SYNC data column 11 and three burst indicator subcode (BIS) data columns 12, wherein the LDC data columns are separated into four LDC blocks 13 by the SYNC data column 11 and three BIS data columns 12. The original LDC data are discontinuous and interleaved into different LDC blocks 13. Some ECC encoding or decoding techniques were described in U.S. Pat. No. 6,378,100, U.S. Pat. No. 6,367,049, U.S. Pat. No. 6,604,217 and U.S. 2003/0208714, wherein U.S. Pat. No. 6,378,100 disclosed a method for encoding multiword information, U.S. Pat. No. 6,367,049 disclosed an encoding method by interleaving, U.S. Pat. No. 6,604,217 disclosed a decoding method using synchronization (SYNC) codes, BIS codes or their dynamic or static combination as an erasure, and U.S. 2003/0208714, a continuation application of U.S. Pat. No. 6,604,217, further disclosed a method using SYNC code as an erasure indicator. Further, Narahara et al. disclosed an error correction method using LDC and BIS codes that was published in Jpn. J. Appl. Phys. Vol. 39 (2000) pp. 912-919.
However, the patents and article mentioned above only raised a concept of methods for decoding ECC data, i.e., they do not explicitly disclose practical implementation methods. Under such circumstances, it is necessary to develop a useful implementation method and apparatus for decoding ECC data.